Valve-gear for steam-engines



(Modem W. JOHNSON. Valve Gear for Steam Engines;

No. 231,228. Patented Aug. 17, 1880-.

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N.PETERS. FHOTOJJTNOGRAPHER, WASHINGYOII. D.\O.

UNITE STATES PATENT OFFICE...

WILLIAM JOHNSON, OF LAMBERTVILLE, NEW JERSEY.

VALVE-G EAR FOR To all whom it may concern Be it known that I, WILLIAM J oHNsoN, a citizen of the United States, residing at Lambertville, in the county of Huuterdon and State of New Jersey, have invented certain new and useful Improvements in Valve-Gears for Steam-Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

My invention relates to that class of steamengincs in which the point of cut-off is determined and controlled automatically by the speed of the engine.

It consists, briefly, in the arrangement of a compound or double eccentric, composed of an inner eccentric and an outer eccentric ring, the said outer ring being attached to the shaft, with which it revolves in such manner as to permit of its free adjustment to the desired extent, both in the amount of its eccentricity and change of position, said adjustment being effected by the automatic action of a governor upon the inner eccentric.

In the drawings, Figure 1 is a plan View. Fig. 2 is an end view. Fig. 3 is a plan and sectional view of the complete eccentric, and Fig. 4 is a plan and sectional view of the sloted disk.

Similar letters refer to similar parts throughout the several views.

A is the engine-shaft, revolved by the action of the steam upon the piston in the usual manner.

F is an eccentric arm or disk, solidly attached to shaft A, in which there is a slot or recess, f.

B is the outer eccentric ring, having a fixed stud or pin, H, projecting therefrom, and which is made to fit and slide freely in slot f.

O is the inner eccentric, fitted within the eccentric ring B, and having a toothed pinionwheel upon one side, which forms a part of said inner eccentric and movable therewith.

L is a large disk (or it may be the fiy-wheel STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 231,228, dated August 17, 1880.

Application filed June 12, 1880.

(Model) of the engine) firmly attached to and revolving with shaft A.

S S are toothed sectors pivoted to large disk L, the teeth of which engage with the teeth of pinion E.

W W are weighted levers attached to seetors S S.

O O are springs connecting with large disk L and sectors S S.

The operation is as follows: The weighted levers and springs are adjusted to an equilibrium for the desired speed of the engine. Any variation from the speed so established will cause the weighted levers to move out from or in toward the center of the shaft, just in proportion as the centrifugal force of the weights or tension of the springs preponderates one over the other, and any change so occurring in the position of the weighted levers will cause a corresponding change of position and throw of the eccentric by the action of the toothed sectors and pinions in revolving the inner eccentric upon the shaft, while the outer eccentric ring is carried around with the shaft by the slotted disk, such change being communicated to the cut-off valve by means of the eccentric strap and rod M, with or without the interposition of a rock-shaft, and in the usual manner.

It will be seen that the inner eccentric and outer eccentric ring may change relations with the shaft and governor--that is to say, the outer eccentric ring may be connected to the governor and the inner eccentric to the shaft without changing the result.

I am aware that one eccentric has been placed within another previous to my invention, for the purpose of permanently adjustin g the throw of an eccentric for steam-engines, and therefore do not claim, broadly, as my invention the placing of one eccentric within another for such purpose. Neither do I claim the precise form or construction or proportion of all or any of the parts; but

What I claim as my invention, and wish to secure by Letters Patent, is-

1. In combination with the driving-shaft of an engine, an outer eccentric ring and inner eccentric provided with a pinion operated up on by sectors which are moved positively by purpose substantially as described and set centrifugal force, as and for the purpose set forth. :0

2. In valve-gear for engines, the eolnhinnnature in presence of two Witnesses. 5 tion of the outer eccentric ring and inner ec- WM. JOHNSON.

centric with the fixed and slotted disk, toothed Witnesses: Sectors, andpinion-wheel,weighted levers, and II. 13. MOULTON, springs, combined in the manner and for the GEo. W. \VARD;

forth. In testimony whereof I have afiixcd my sig- 

